Relief valve for vaporizer



Jan. 24, 1956 D, J, REED 2,731,801

RELIEF VALVE FOR VAPORIZER Filed Aug. 7, 1952 FIG- 1.

/1 111/ vllllllllllll INVENTOK Dau-nei Reed ATTORNEYS.

United States Patent RELIEF VALVE FOR VAPORIZER Daniel J. Reed, Milwaukee, Wis., assignor, bv mesne assignments, to .lohn M. Stover, Oklahoma City, Okla.

Application August 7, 1952, Serial No. 303,198

2 Claims. (Cl. 62-1) This invention relates to a relief valve for a vaporizing apparatus and more particularly to a valve adapted to relieve excessive vapor pressure in a liquid fuel vaporizing chamber by discharging the vapor under excessive pressure into the liquid fuel feed line.

Liquid fuels such as propane, butane and the like, when employed in internal combustion engines are ordinarily vaporized in a single or multi-stage vaporizing apparatus and the pressure of the vaporous fuel regulated before the fuel is drawn into the intake manifold by engine suction. Occasionally during engine operation, and more particularly at high engine speed, incomplete vaporization occurs. That is, a slug of liquid fuel will pass into the vaporizing chamber without being vaporized. This slug of liquid will collect in the bottom of the vaporizing chamber in the form of a pool. Then if the engine is shut down, the valve admitting fuel to the vaporizing chamber will be closed as will the discharge valve through which the fuel vapors leave the chamber. Heat will be conducted through the casing of the apparatus to the liquid trapped in the vaporizing chamber with the result that the liquid will vaporize and generate a considerable pressure. It is essential that this pressure be vented or the pressure responsive valve operating mechanism in the chamber will be seriously damaged by this excessive pressure.

In some instances, excessive pressure in the vaporizing chamber has been relieved to the atmosphere by a relief valve carried in the casing of the apparatus. This practice causes loss of fuel and involves considerable hazard for the infiammable vapor is discharged into the engine in contact with the hot engine parts.

One object of the invention is to provide a simple and effective relief valve for a vaporizing apparatus which will eliminate the loss of fuel vapor to the atmosphere.

Still another object of the invention is to provide a relief valve which may be consolidated with the structure of an existing vaporizing apparatus without re-building or altering the apparatus.

Under the invention a valve assembly is provided in conjunction with the fuel inlet passage or chamber and the primary chamber of the unit to vent vaporized fuel back into the inlet passage from the primary chamber when the pressure in the primary` chamber due to excessive vaporization of fuel therein reaches a predetermined pressure that would be hazardous for the unit to contain.

Further objects and advantages of the invention will appear hereinafter in the course of the following description of the drawings.

In the drawings:

Figure l is a sectional view of a vaporizing apparatus utilizing the relief valve of the present invention and showing the valves and their operating levers rotated into a common plane for simplicity of illustration;

Fig. 2 is a face view of the casing, as viewed from the left in Figure l, with the diaphragm removed, parts being shown in section;

Fig. 3 is a fragmentary View showing a second embodiment of the invention; and

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and pressure regulating apparatus substantially as shown in application Serial Number 302,586 filed August 4, 1952, and assigned to A. O. Smith Corp., Milwaukee, Wisconson. The apparatus comprises a generally hollow casing l which is configured to define a primary or vaporizing chamber 2 on one face and a secondary or regulating chamber 3 on the other face. Chambers 2 and 3 are separated by central wall 4 of casing 1.

A heating chamber 5 is provided in casing 1 beneath vaporizing chamber 2 and defines a generally U-shaped passageway for the circulation of a heating medium such as a portion of the engine coolant or any heated fluid. An inlet conduit 6 which provides communication with a source of the heated medium is joined to one end of chamber 5 and a discharge conduit`7 is attached to the other end of chamber 5.

Casing 1 is also provided with a fuel inlet chamber 8 which extends beneath chamber 2 between the legs of the U-shaped heating chamber' 5. The heating medium owing within chamber 5 serves to heat the liquid fuel before said fuel is introduced into vaporizing chamber 2 and also to heat the vaporized fuel within chamber 2.

An inlet passage 9 provides communication between one end of chamber 8 and the exterior of casing 1. A conduit 10 joined to passage 9 establishes communication between passage 9 and a tank or other source of liquid fuel, not shown.

The other end of fuel chamber 8 communicates with a radial passage 11 which extends inwardly from the exterior of casing 1.

A fitting 12 having a passageway therethrough is threadedly engaged in a suitable opening in wall 4 of casing 1 and establishes communication between the primary chamber 2 and the inner extremity of radial passage 11. A gasket 13 is interposed between a shoulder of fitting 12 and the wall 4 to seal the joint. The outer end of fitting 12 is provided with a valve seat 14.

A valve member 15 is employed to regulate the flow-of liquid fuel through fitting 12 into vaporizing chamber 2. Valvemember 15 is controlled by a primary diaphragm member 16 which enclosesl the open side of chamber 2 and responds to pressure differences in the chamber 2 member 22 and thereby regulates the ow of vaporousA fuel through the orifice of fitting 20 to chamber 3. vThe operation of secondary valve member 22 is controlled by a secondary diaphragm member 23 which encloses the open side of chamber 3 and is responsive to pressure variations in chamber 3 caused by engine suction.

An outlet port 24 is provided in the outer wall of casing 1 and establishes communication between secondary chamber 3 and the manifold of the engine.

A body of vaporous fuel at a pressure slightly above atmospheric is maintained in secondary chamber 3, and as this fuel is drawn into the manifold by engine suction diaphragm-member 23 responds to the pressure decrease in chamber 3 and opens valve member 22 thereby permitting vapor at a pressure of about 5 pounds per square inch above atmospheric in chamber 2 to pass into Vchamber 3. As vapor passes from chamber 2 to chamber 3 the pressure is reduced in chamber 2 and the primary diaphragm member 16 responds to the pressure decrease in chamber 2 and opens valve 15, thereby permitting liquid fuel to enter chamber 2.

The central wall 4 of casing 1 is provided with a pas sage 25 which establishes communication between chamber 2 and radial passage 11. Passage 25 serves as a vent whereby excessive pressure in chamber 2 may be relieved to the inlet fuel chamber 8.

A relief valve assembly 26 is disposed in radial passage 11 to regulate the flow of vapor being vented to chamber 8. Valve assembly 26 comprises a generally cylindrical valve member 27 the upper end of which engages the inner extremity of radial passage 11 the joint being seated by a gasket 28. Valve member 27 is provided with a longitudinal port 29 which registers with passage 25. A portion of the side surface of valve member 27 has a fiat configuration to permit liquid fuel in passage 11 to pass through fitting 12 to chamber 2. The outer end of valve member 27 is provided with a valve seat 30.v

A valve 31 regulates the ow of vapor through member 27 and carries a resilient washer 32 in position to engage and seal valve seat 3i?. Valve 31 is adapted to slide within passage 11 and has a generally square configuration in cross-section to provide a clearance between valve 31 and the Wall of passage 11, thus permitting liquid fuel in passage 11 to pass around valve 31 through fitting 12 and hence to chamber 2 when the associated valves are open.

The outer end of valve 31 is formed with an annular recess 33 which receives one end of a spring 34. The other end of spring 34 bears against the inner end of a plug 35. Plug 35 is threadedly engaged within radial passage 11 and serves to close off passage 11 to the atmosphere. Spring 34 urges valve 31 to the closed position.

During engine operation, particularly at high engine speed or sudden engine fuel demand, slugs of liquid fuel may occasionally pass through fitting 11 into chamber 2 without being completely vaporized. If engine operation is continued, heat will be conducted from the heating rnedium circulating within chamber to the liquid fuel which accumulates in the bottom of chamber 2 and the fuel will be vaporized. However, if the engine is shut down while liquid fuel is in chamber 2 the valves 15 and 22 will close as there is no engine suction or demand for fuel. The liquid fuel thus isolated in chamber 2 will be vaporized by the heat remaining in the heating medium, and considerable vapor pressure will be built up in chamber 2.

This excessive pressure, if not relieved, is apt to cause Y over-flexing and hence damage to the diaphragm mem ber 16.

However, under the invention the vapor which is under excessive pressure in chamber 2 passes through passage 25, valve member 27 and forces valve 31 away from valve seat 30, thereby permitting the high pressure vapor to vent into radial fuel passage 11 which is connected to fuel inlet chamber 8. When the vapor pressure in chamber 2 reaches equilibrium with the liquid fuel pressure in passage 11, valve 31 will close. By venting the vapor into the radial fuel passage 11 rather than into the atmosphere the fuel vapor is conserved and available for future use. In addition there is no fire hazard presented by venting the vapor into passage I1 as there would be in the case of fuel vapor being vented into the atmosphere in contact with hot engine parts.

Figs. 3 and 4 show a second embodiment of the present invention in which the check valve is located in the inlet valve lever instead of the inlet port in the casing.

A valve member 36, corresponding to valve member of the first embodiment, is employed to regulate the flow of liquid fuel through a fitting 37, corresponding to fitting 12, into vaporizing chamber 38.

Valve member 36 comprises a valve lever 39 which is pivotally secured between brackets 40 which extend outwardly from wall 41, corresponding to wall 4, by pin 42.V

The outer portion of valve lever 39 is formed with a i' to pivot valve lever 39 to the closed position whereby the opening in valve seat is sealed by sealing member 44. The inner extremity of lever 39 is also provided with a knob-like projection which is in contacting relation Y with diaphragm member 51. When the vapor pressure in chamber 38 decreases below the predetermined equilibrium pressure, diaphragm member 51 will act to pivot lever 39 against spring 47 and open valve 45 to admit additional fuel to chamber 38.

To relieve excessive pressure in the vaporizing or primary chamber which may arise under conditions hereinbefore described, the outer portion of valve lever 39 is configured to define a recess 52 which houses a relief valve member 53.

Relief valve member 53 includes a disk 54 having an opening therethrough and defining a valve seat. Disk 54 carries a sealing member 55 and is received within an annular groove 56 formed in recess 52 adjacent the open end thereof. The edge of annular groove 56 is bent inwardly to retain valve seat 54.

A valve 57 regulates the flow of vapor through valve seat 54. One end of valve 57 is formed with generally spherical recess 58, and the annular edge bordering recess 5S is in position to engage sealing member 55 and close off the flow of vapor through valve seat 54.

The other end of valve 57 is formed with a reduced stem and is received within one end of a spring 59. The other end of spring 59 bears against the end of recess 52. Spring 59 urges valve 57 to the closed position.

A clearance is provided between valve 57 and the wall of recess 52 by forming valve S7 with a square cross section. The clearance permits vapor being vented through valve seat 54 to pass around valve 57 into recess 52.

Washer 44 is formed With an opening 60 therethrough which registers with the opening in fitting 37. A ferrule 61 is disposed within opening 60 to keep the same from closing when washer 44 is in compressed engagement with valve seat 45.

A passage 62 in valve lever 39 establishes communication between recess 52 and the opening 60 in washer 44 and thereby provides a liow path for vapor from recess 52 through opening 60 and fitting 37, to radial fuel passage 63, which corresponds to passage 11.

When the pressure of the vapor in chamber 38 builds up in excess of the pressure of the liquid fuel due to slugs: of unvaporized fuel being vaporized in chamber 38 after engine shutoff, the high pressure vapor will force valve S7 to the open position and will be vented to the recess 52 and thence to fuel passage 63.

This embodiment of the present invention may be conveniently incorporated into the structure of many existing vaporizers without altering or rebuilding the structure of the apparatus by merely substituting valve lever 39 containing the relief valve member 53 in place of the former valve lever.

The invention provides a simple device forirelief 0f' an end thereof communicating with the vaporizing chamber, a biased valve member disposed within said Vaporizing chamber and carrying a valve in position for biased closing of the valve across the entry of the inlet fuel passage to control the entry of liquid fuel into said chamber, said valve member being formed with a recess therein communicating with the vaporizing chamber and having a passageway providing communication between said recess and said inlet fuel passage when the valve is closed, said passageway being axially aligned with said inlet fuel passage and communicating directly with said end of the inlet fuel passage when said valve member is positioned to close off the entry of liquid fuel into the vaporizing chamber, and relief valve means disposed within said recess in position to open the recess for entry of fuel vapor into the recess from the vaporizing chamber for discharge to the inlet passage when the vapor pressure in said Vaporizing chamber exceeds the pressure of the liquid fuel in the inlet fuel passage.

2. In a vaporizing apparatus for vaporizing liquid fuel, a housing, a vaporizing chamber in said housing, a fuel inlet passage extending through the housing and communicating with the vaporizing chamber, a hollow valve member fulcrumed within the vaporizing chamber and having one end portion congured to define a recess therein in communication with the vaporizing chamber,

valveA means carried by said end portion of the valve member and disposed to control the entry of liquid fuel from the fuel inlet passage .into the vaporizing chamber and having an opening therethrough, said opening communicating with said recess and being disposed in direct registry with the inlet fuel passage when said valve means is positioned t'o close off the entry of liquid fuel into the vaporizing chamber and being disposed out of direct registry with said inlet fuel passage when the valve means is positioned to permit the entry of liquid fuel into the vaporizing chamber, and relief valve means disposed within said recess and adapted to permit entry of fuel vapor into said recess from the vaporizing chamber and discharge to the fuel inlet passage when the vapor pressure in said vaporizing chamber exceeds the pressure of the liquid fuel in the inlet fuel passage.

References Cited in the file of this patent UNITED STATES PATENTS 2,248,222 Ensign July 8, 1941 2,258,003 Dickson Oct. 7, 1941 2,493,369 Smith et al. Ian. 5, 1950 2,596,982 Chisholm, Ir. May 20, 1952 2,618,935 Malir, Jr Nov. 25, 1952 

